Epoxy beta-lactones



United 2,940,932 EPOXY BETA-LACTONES William J. Sullivan,Dakland,-Calif., assignor to Shell Oil Company, a corporation ofDelaware No Drawing. Filed Apr. 14, 1958, Ser. No. 728,077 5 Claims.(Cl. 260-3439) This invention relates to novel epoxy lactones and to aprocess for their preparation. More particularly, the invention relatesto new and useful epoxy beta-lactones and to a process for preparingthem from epoxyaldehydes and ketenes.

Lactones generally are useful organic compounds for a variety ofpurposes. They are employed as ingredients .of perfumes and are, sincethey are known to have rapidly under ordinary reaction conditions. It isfor this.

reason that catalysts are ordinarily employed to promote theketene-carbonylic compound reaction. For example, in U.S. Patent2,356,459, issued August 22, 1944, to F. E. Kung, the reaction betweenketenes and carbonylic compounds to form beta-lactones is conducted withthe aid of a Friedel-Crafts catalyst, such as boron trifluoride.Caldwell, in U.S. Patent 2,450,116, issued September 28, 1948, preparesbeta-lactones from similar reactants employing metal perchloratecatalysts, and in U.S. Patent 2,466,420, issued April 5, 1949,Hagenmeyer discloses the use of metal salts of aliphatic monocarboxylicacid catalysts. I

Surprisingly, I have discovered that a newclas's of beta-lactones, epoxybeta-lactones, may be prepared from ketenes and epoxy carbonyliccompounds without theuse of catalysts and under conditions wherein theepoxy ring of the carbonylic reactant is preserved intact in theheta-lactone product.

:It'is an object of my invention to provide, a new class of'beta-lactones. A further object of my invention is the provision ofbeta-lactones containing, in addition to the lactone ring, an epoxyring. A still further object of my invention is the provision of aprocess for preparing epoxy lactones from epoxyaldehydes. Still anotherobject of my invention is the process whereby epoxyaldehydes may bereacted with ketenes to form epoxy beta-lactones without the use of acatalyst and wider conditions such that the epoxy ring is preservedintact Other objects will be apparent from the following description ofthe invention.

My invention comprises a novel class of beta-lactones, epoxybeta-lactones. These lactones are characterized by possession both ofthe vicinal epoxy, or oxirane, ring tes Patent G where R is selectedfrom the class of monovalent radicals consisting of the hydrogen atomand hydrocarbyl radicals. These new and useful compounds are prepared,in my invention, by reacting together an epoxy-aldehyde and a ketene.

The new epoxy beta-lactones are best described by reference to themethod by which they are prepared, and thus by consideration of thereactants employed to form them, that is, by a discussion of the natureof the epoxyaldehydes and ketenes used.

Epoxyaldehydes are those compounds containing both the formyl, -CHO,group and the epoxy ring L In general, they are prepared by theepoxidation of the olefinic bonds of unsaturated aldehydes. Suitablealdehydes, for example, 2-methyl-2,3-epoxypropionaldehyde, are preparedby epoxidation of alpha-methacrolein, 2,3- epoxy butyraldehyde fromcrotonaldehyde, 2,3-epoxy-2- methyl butyraldehyde from tiglic aldehyde,beta-phenyb 2,3-epoxy propionaldehyde from cinnamaldehyde, and so forth.While the most reactive class, and therefore the preferred class, ofepoxyaldehydes are those 2,3- epoxyaldehydes prepared from alpha,beta-unsaturated aldehydes, other types of epoxyaldehydes having one ormore epoxy groups are included within the scope of such reactants.Examples include the epoxy compounds prepared by epoxidation of theolefinic linkages of such aldehydes as 3-butene-1-al,citral,xcitrone1lal, rhodinal, 1-formyl-3-cyclohexene, and the like. 7

Of all the epoxyaldehydes, the most preferred is glycidaldehye, theexpoxy compound prepared by epoxidation of acrolein. Sinceglycidaldehyde includes a terminal 2,3-epoxy group, it is a very activereactant and produces as well valuable epoxy beta-lactones.

The ketenes which are employed in the process of my invention can berepresented by the formula wherein the Rs represent the same ordifferent monovalent radicals selected from the group consisting of thehydrogen atom and hydrocarbyl compounds. Of these, the parent compound,ketene, CH C=O, is preferred as the ketene in my process, but also thescope of the invention are its alkyl and aryl homologs.

Examples of operative ketenes include the aldoketenes such as methylketene, ethyl ketene, propyl ketene, butyl ketene, phenyl ketene, benzylketene, and naphthyl ketene; and the ketoketenes such as dimethylketene, diethyl ketene, dipropyl ketene, methyl ethyl ketene, diphenylketene, propyl phenyl ketene, dibenzyl ketene, and so forth.

The reaction between the epoxyaldehydes and the ketenes may be carriedout within a wide range of reactant proportions. In View of the tendencyof ketenes to polymerize, however, the use of a large excess of theketene reactant over the aldehyde is not recommended. The epoxyaldehydereactant, however, is very stable under the reaction conditions of ourprocess and there'- fore the use of greater than equimolar amounts ofepoxyaldehyde is not harmful. The preferred reactant ratio for mosteconomical conduct of my process is that in which from substantiallyequimolar amounts of epoxyaldehyde and k'etene reactant to 2 moles ofthe aldehyde per mole of ketene are employed, since no particularadvantage is obtained by large excesses of either reactant.

In accordance with my invention, the reaction between epoxyaldehydes andthe ketenes to form epoxy betalactones'is conducted at temperatures suchthatthe reaction goes smoothly without either undue polymerization of'the ketene or' the lactone product, and without attack on the epoxyring. The temperature range for these conditions, to obtain is thatbetween about -49 C. and about +30 (3., while the preferred range, forreasons of reaction speed and convenience, is that from about 7 -'10 c.to about +10 0. r

The reaction is not dependent on the physicalfstate of the reactants,and therefore may be conducted in the presence or absence of an inertsolvent. Suitable solvents include benzene, toluene, xylene, theparaflins that are liquids at the reaction temperatures, dioxane,diethyl ether, andthe like. In this way, solid, viscous orvolatile ractants mayjconveni'entl'ybedissolved inthe solvent for ease in handlihgand reacting. a

As has been pointed out, the reaction between the as zincchloride, zincacetate, zinc nitrate, boric acid, or

mixed aluminum-silicon-zirconium oxides,. may be desirable. 1 7 d c fThe processfof my reaction may be carried out in a continuous,semi-continuous or batchwise manner' by 7 rnethods. already extensivelydescribed in the lactoneliterature. At the close of my reaction, it is;convenient to separate'the reactants from the product bysuch-arwellknown method as vacuum'distillation. Thus, the keteneandaldchydereactants, having a lower molecular weight 7 than the epoxybeta-lactone product, may be readily flashed from the reaction.mixturaand ther'esidua'l lactone, may then berecovered and pu ifiedbysolvent or distillation methods. t j I v I The product epoxybeta-lactones thus prepared are determined by the natureof theepoxyaldehyde 'and gen atom and hydrocarbyl radicals, and n is at leastzero. Preferably, such hydrocarbyl radicals are drawn from alkylradicals such as methyhethyl, propyl,butyl, pentyl, decyl, and the like,particularly those having. fewer than about five carbon atoms, andfromaromatic monovalent radicals, including phenyl and suchalk'ylesubstituted phenyl radicals as benzyl, tolyl, xylyl, and thelike. Polyepoxy beta-lactones, such as are prepared from diepoxyaldehydes, are also included within the scope'of my invention. t i

By virtue of their possession of the epoxy group and. the versatilebeta-lactone configuration, the epoxy betalactones of my invention areuseful'for a variety of reactions. Both types of oxygen-containing ringsmay be employed in polymerization reactions. For eriample, such alkalimetal salts as potassium carbonate maybe "used to produce solidpolyepoxide polyester acids which can be' hydrolyzed to monomericbeta-hydroxy: epoxy acids; The lactones' may also be copolymerizedthrough their lactone and epoxy ringswith such other compoundsas' epoxyethers and polyhydroxy compounds. The epoxy 6Q- polymers or the firsttypeare'us'eful, by virtue'of'thc'ilf hardness and flexibility, assurface coatings. V 55 The coploymers of the second type, producedby'copolymerization of my epoxy beta-lactones with such conipounds'asethylene glycol, propylene glycol, hexanediol- 1,4, pentaerythritol, andthe like, are film-forming materials which are compatible withcelluloseethers, cellulose es'ters, polyvinyl halides and the-like andgiveadditional stability, flexibility and toughness to thesematerials.Compounds'of this type are analogous to those described in US. Patent2,455,731, issuedDecember'Y,

19 48 to I. R. Caldwell.

The-following examplesill illustrate the nature and properties ofthe'novel'epoxy betalactone's ofthisfinvention, as well as the processby which theyare' pre pa'red, It should be understood, however, that.the' examples are merely illustrative and 'are'not to beTre'gardedaslimita" tions' to the appended claims, since the-basic teachingslight-colored'mobile liquids. Their structure is, of course,

ketenereactants. Exemplary .lactones are shown inthe' following tabletogether: with thereactants' from-which:

they are prepared.

a was then removed under reduced pressure. 'lfheunre therein may bevaried as will beunderstood byori'e-skilled in the art. In the examples,the ingredie'nts are expressed in pa'rts'by weight unless otherwiseindicated. 1 C

-Examplell i l A ketene generator, comprising an..electric gridjar '1ranged inrefluxing acetone, was setup todeliver ket'ene at a-known rate.With this generator, 03 2811111 016 of ketene was bubbled 'into .0.50-mole of glycida ldehyde in 200 ml. of'diethyl ether at 0 C. i Thereactionmixtur was allowed to stand for several hours, jandj th e iet'her acted'ketene and glycidaldehyde werethen flashed ofi,

' and the product epoxy beta-lactone distilled at 84 85.

' 'A ldehyde Keteue Lactone glyctdaldehyde ketene 4,5-epoxy-beta-penta-7 i lactone. z-methyl-zfi-epoxy prodo4,5-epoxy-4emethyl-betapionaldehyde. pentalactc'ne. glycidaldehydemethyl ketene 4,5-epoxy-2-methyl-beta- 1 i peutalactone.

beta-phenyl-ZSepoxy prodlethylketene-.. 5-pheny1-2,3-epoxy -2,2-ptonaldehyde. i diethyl-beta-pentalac- 4 tone.

3,4 epoxy-pentanal propylketene.-. 5,6ep0xy-2-pr0pyl-betaheptalactone.2,6,-tlimethyl-2,"-e 'loxyv ketene 8,9-epoxy-5,9-dimethyloctsnal.beta-decalactone 3,4sepoxycyclohexana1..- do sA-epoxycyclohexyh tbeta-proplolactone.

iradicals selected from the class; consisting ot the'hydro- C. at'about3 mmzof mercury; This prod'uct had areit'ractive index at 20 C. of1.4530.

A 70% yield was thus obtained. Upon analysis; following data wereobtained: I

' lfipoxide Ester. Acidity Percent 0 H Value; Value, Value,

' V eq./g. eq./10tlg. eq./10( g.-

Calculated for Cantos-.." 52.6 5.26 ,o;,s17 Found 52.3 ,5.4 0.846

Another sample of the4,5-epoxy-beta pentalactone prepared from ketene'and 'glycidaldehydewas reacted with 100 parts of ethanoland 0.1g. ofp-toluenesulfonic acid,

and the resulting mixture was'heated at 100 Cwfor- 3' hours. Theunreacted ethanol was removed under reduced pressure and the residueneutralized with dilute alkali, extracted with ether and dried overanhydrous magnesium sulfate. The product boiling at 90-95 C.

5 at less than 1 mm. was collecteu, and the resulting ester analyzed toyield the following data:

Ester Percent H Value,

eq./100 g Calculated for 0 11150 53. 6 8. 8 0. 48 Found -t 52. 5 8. 750. 42

These data correspond to an ether-ester produced by alcoholysis of acompound having the structure When ketene, produced as in the previousexample, is passed into a 200 ml. dioxane solution containing 0.25 moleof 2,3-epoxy-beta-phenyl propionaldehyde under the conditions noted, asimilar amount of 4,5-epoxy-5-phenylbeta-pentalactone is obtained.

Example III When diphenyl ketene is substituted for the ketene inExample I, a compound having the formula H=CL\CHCHO CaHr- -C==O JeHl isobtained.

Example IV By using 2,3-epoxy butyraldehyde in Example I in place ofglycidaldehyde, 4,S-epoxy-beta-hexalactone is obtained.

6 Example V By using the reaction conditions of Example I and combiningml. ether solutions containing, respectively, 0.25 mole of methyl keteneand 0.31 mole of 3,4- epoxy-pentanal,5,6-epoxy-2-methyl-beta-heptalactone is prepared.

I claim as my invention:

1. The epoxy beta-lactone having the formula C ;CH(CH:)nCHO where n isan integer from 0 to 4. 3. 4,5-epoxy-beta-pentalactone. 4.4,S-epoxy-beta-hexalactone. 5. 4,5-epoxy-2,2-diphenyl-beta-pentalactone.

References Cited in the file of this patent UNITED STATES PATENTS2,786,068 'Frostick et a1 Mar. 19, 1957 FOREIGN PATENTS 500,661 CanadaMar. 16, 1954

1. THE EPOXY BETA-LACTONE HAVING THE FORMULA